With respect to a semiconductor device which communicates data by wireless communication, an object of the present invention is to improve sensitivity of an antenna and to protect a chip from noise without increasing the size of the device. A coiled antenna and a semiconductor integrated circuit which is electrically connected to the coiled antenna are included. The semiconductor integrated circuit is arranged so as to overlap with the coiled antenna. In this manner, arrangement of the coiled antenna and the semiconductor integrated circuit in the semiconductor device is devised, so that sensitivity of the antenna can be improved and power enough to operate the semiconductor integrated circuit can be obtained without increasing the size of the device.